Synthesis Of New Nanostructured Metallic Materials And Studies On Their Catalytic And Surface Properties

Nanostructure metallic materials have been widely used in catalysis, electrochemistry, spectrometry, and surface modification etc. The synthesis and control of nanostructure metals of various structure and morphology resulting in fascinating functions and enhanced properties has been the subject of scientists' great attention. Among them, hollow metal nanosphere, mesoporous metal and other one or two-dimensional nanostructure metal materials are most thoroughly investigated. Owing to unique chemical, optical and electrical properties, nanostructure metal materials of various structure and morphology have been widely used in surface science, trace analysis, nanosensor and nanoelectronics. Generally speaking, regular amorphous alloy catalysts are usually prepared via direct chemical reduction, these particles are nonporous with broad size distribution. Moreover, they are easy to suffer from agglomerating, sintering and even losing, which limit their applications in catalysis. This work develops new approaches to design high surface area nano-assembly system with mesopore channels and uniform particle size via control of structure and morphology of amorphous alloy and metal, leading to the enhanced efficiencies in catalytic and analytic fields. The total work could be described as follows..An effective method for the preparation of amorphous Ru-P hollow nanospheres catalyst has been developed. Microemulsion formed with surfactant, water and oil is used as the template. The formation mechanism is discussed briefly. We could change the preparation conditions such as type of surfactant, amount of surfactant and cyclohexane to tune up morphology of the catalyst. Owing to its unique hollow nanosphere structure, the catalyst shows better catalytic efficiency and longer durability than regular amorphous Ru-P, Ni-P, Co-P alloy and industrial Raney Ni in glucose hydrogenation to sorbitol reaction.Ru-B amorphous alloy catalyst with mesoporous structure has synthesized by chemical reduction co-assembling with nonionic surfactant in lyotropic liquid crystalline phase. The catalyst sample is present in uniform nanospheres with the average particle size around 80 nm and worm-like mesopores. During liquid-phase maltose hydrogenation to maltitol, such catalyst exhibits much higher activity and recycle ability than the regular amorphous Ru-B solid nanoparticles, pure Ru powder and Raney Ni catalyst due to the higher surface area and mesoporous structure.Hollow gold nanospheres with nanopinholes are prepared by chemical reduction based on synergetic self-assembly of metal ion/surfactant composite vesicle template. The average particle size is around 60 to 80 nm and the shell thickness could be easily adjusted by varying the reaction temperature. This material could be served as substrates for surface-enhanced Raman scattering, which exhibit much higher surface enhancement than the solid gold nanoparticles in case of Rhodamine 6G as a molecule probe. Moreover, it could also be used in the modified electrode to detect DNA. The result indicates that the DNA biosensor containing hollow gold nanospheres is more sensitive than that containing gold nanoparticles of the similar size.